The present invention relates to an electronic semiconductor device for protecting integrated circuits from electrostatic charges, as well as to a process for producing the device.
Protection devices for integrated circuits, particularly for linear integrated circuits, against electrostatic discharges of both signs are known in different embodiments. Some solutions, as an example, employ the base-emitter or base-collector junctions defining diodes and resistors according to different configurations. Other solutions comprise SCRs to be connected between the input terminal of the integrated circuit to be protected and a reference-voltage line.
These solutions, however, are not completely satisfactory from several points of view. In particular, these known embodiments require a relatively large integration area which contributes to increasing the overall dimensions of whole including the integrated circuit and the protection device.
Another disadvantage of the known solutions, particularly of those employing diodes and resistors, consists in that they have a relatively high series impedance, and therefore dissipated power is quite high. Therefore, these structures are effective against damaging voltages below a certain value, and cannot be employed in those applications where the integrated circuit is to be protected against very-high-voltage electrostatic discharges.